Objective To establish a radiation-resistant cell subline from a human small cell lung cancer(SCLC) cell line NCI-H446, providing a pairing research tool for investigating mechanism of radiation tolerance and the reverse strategy in lung cancer. Methods The NCI-H446 cell was radiated repeatedly by increased dose of radiation gradually(total 7500cGy) and a radiation-resistant cell substrain was induced and selected from the survival of cells. The doubling time and cell cycle distribution of the substrain were detected by ATP kit and flow cytometry Assay respectively;Radiation biology parameters were calculated and analyzed by cell survival curve fitting from multi-target model, SF=1-(1-e-D/D0)N. Results Comparing with the control, The resistant substrain radiobiology parameter values were D₀(1.9673,2.2756), N(1.0016,2.6008), Dq(0.6783,1.6860)and SF₂(0.3623,0.7134) respectively. Cell morphology is more slender and has more tentacles. The SF₂ value of radiation-resistant subline is 1.97 times more than that of wild cell line. The proportion of radiation-resistant cells in G2/M-phase was down to 7.84%, compared with the 18.52% of wild cells. Conclusions A radiation-resistant SCLC subline NCI-H446-R is established and may be a useful tool for studying resistant to radiation of SCLC in the future.