〔Abstract〕 Objective To investigate the optimal setting value of the minimum segment area(MSA) based on the Monaco planning system in the static intensity modulated radiotherapy(IMRT) plan for cervical cancer to improve the accuracy of radiotherapy planning for cervical cancer. Methods A retrospective collection of 10 patients with cervical cancer was performed using the Monaco treatment planning system to design fixed five-field static intensity modulation plans with MSA of 1, 2, 4, 10, 20, 50, 80, and 100 cm2. Each patient received eight radiotherapy plans. The radiotherapy plan with an MSA of 2 cm2was used as the control group to compare the radiotherapy plans with other MSA settings. Under the premise that other optimization objective functions and constraints were the same, only the set value of MSA was changed, and the statistical methods for analyzing of variance and post-hoc comparison were used to study the impact of MSA on radiotherapy plans. Results When MSA was in the range of 10～20 cm2, compared with the control group, the dose of target area and organ-at-risk did not change significantly, but the number of monitor units and subfields began to decrease. When MSA starts from 50 cm2, compared with the control group, the maximum dose(D2%) and the average dose(Dmean) in the target area both increased, and the uniformity index(homogeneity index, HI) and conformity index(conformity index, CI) began to deteriorate. Except for the small intestine average dose(Dmean) that changed slightly with MSA, the exposure to other organs at risk increased with the increase of MSA(P<0.05); the number of monitor units and subfields generally decreased with the increase of MSA. Conclusion In the design of a static intensity modulation plan for cervical cancer based on a Monaco treatment planning system, the optimal setting range for the MSA setting value is 10～20 cm2.