【Abstract】 Objective To investigate the concurrent radiotherapy and FOLFOX6 chronomodulated chemotherapy for patients with locally advanced rectal cancer (LARC) in preoperation. Methods In this study, patients with LARC between January 2012 and June 2016 were included. The patients were divided into experimental group (44 cases) and control group (45 cases). Therapeutic schedule of experimental group were concurrent three dimensional conformal radiation therapy and FOLFOX6 chronomodulated chemotherapy in preoperation, and control group were three dimensional conformal radiation therapy and FOLFOX6 conventional chemotherapy in preoperation. Data was collected on the curative effect, untoward reactions, peroperative complications, tumor marker, immune function index, changes of quality of life. The data of two groups were compared using chisquare test and so on. Results The sphincter preservation rate and downstaging rates in tumor were similarity in the two groups (P＞0.05). The incidence rate of neurotoxicity, digestive tract reaction, anemia in the experimental group were significantly lower than that in the control group (P＜0.05). The carcinoembryonic antigen concentration of two groups, CA199 concentration of experimental group and B cell percentage of control group were decreased significantly after radiotherapy and chemotherapy in preoperative (P＜0.05). CD4 percentage and CD4/CD8 were increased significantly after radiotherapy and chemotherapy in the experimental group in preoperative (P＜0.05). The constituent ratio of reduces the life quality of experimental group was significantly lower than that of control group (P＜0.05). Conclusions The therapeutic effect of concurrent radiotherapy and FOLFOX6 chronomodulated chemotherapy in preoperation to the treatment of LARC was very significant, this therapeutic schedule can reduce the rate of preoperative chemoradiation adverse reactions, and also can strengthen immunity and reduce the impact of life quality of patients to chemoradiation.