Objective Based on apolipoprotein a-I (Apoa-I) gene knockout mice, the role and mechanism of phosphotidylcholine (PC) in improving cholesterol reverse transport were explored. Methods Thirty Apoa-I^-/- mice were randomly divided into an Apoa-I^-/- group, Apoa-I^-/- + HFD group, and Apoa-I^-/- + HFD + PC group using the random number table method ; 30 C57BL/6J mice were randomly divided into a WT group, WT + HFD group, and WT + HFD + PC control groups, with 10 mice in each group. The Apoa-I^-/- group and WT groups were fed basic feed, while the other groups were fed high-fat feed for 8 weeks to establish a hyperlipidemia model. From the 9th week, the WT + HFD + PC group and Apoa-I^-/- + HFD + PC group were given PC 2.5 g/(kg·d), while the remaining mice were given physiological saline by gavage for a total of 4 weeks of intervention. The serum lipid levels of the mice were detected using a fully automated analyzer. Hematoxylin and eosin and Oil red O staining were used to observe pathological and morphological changes, and the COD-PAP method was used to detect cholesterol levels in mouse liver tissue. The ELISA method was used to detect LCTA levels in mouse serum, and RT-qPCR and Western Blot method were used to detect the mRNA and protein expression of cholesterol ATP binding cassette transporter A1 (ABCA1), ATP binding cassette transporter G1 (ABCA1), lecithin cholesterol acyltransferase (LCAT), hepatic lipase (HL), scavenger receptor class B type I (SR-B1), and low-density lipoprotein receptor (LDL-R) in liver tissue. Results Compared with the WT group, the serum lipid levelsof WT + HFD group mice were significantly increased (P<0.01), LCAT levels were significantly reduced (P<0.05), hepatic fat vacuoles were obvious, hepatic lipid deposition was significant, and liver tissue TC levels were significantly increased (P<0.01). The mRNA and protein expression of ABCA1, ABCG1, LCAT, SR-B1, HL, and LDL-R were significantly reduced (P<0.05, P<0.01). Compared with the WT + HFD group, serum lipid levels in the WT + HFD + PC group were significantly reduced (P<0.05, P<0.01), LCAT levels were significantly increased (P<0.05), hepatic fat vacuoles were significantly reduced, hepatic lipid deposition was alleviated, and liver tissue TC levels were significantly reduced (P<0.05); mRNA and protein expression of ABCA1, LCAT, SR-B1, HL and LDL-R were significantly increased (P<0.05, P<0.01). The serum levels of TC, TG, and LDL-C were significantly increased, while the levels of LCAT、HDL-C were significantly reduced (P<0.05, P<0.01) in the Apoa-I^-/- + HFD group mice. Hepatocytes underwent balloon-like transformation, liver lipid deposition was significantly aggravated, and liver tissue TC levels were significantly increased (P<0.05). The mRNA and protein expression of ABCA1, LCAT and HL were significantly reduced (P<0.05, P<0.01). Compared with the WT + HFD + PC group mice, the Apoa-I^-/- + HFD + PC group mice showed a significant increase in serum lipid levels (P<0.05, P<0.01), LCAT levels were significantly reduced (P<0.05), significant hepatic lipid vacuoles, significant hepatic lipid deposition, and a significant increase in TC levels in liver tissue (P<0.05). Their mRNA and protein expression of ABCA1, ABCG1, LCAT, SR-B1, and HL were also significantly reduced (P<0.05, P<0.01). Conclusions Phosphatidylcholine can improve dyslipidemia by interfering with Apoa-I and thus regulating cholesterol reverse transport.