Abstract: Objective To evaluate if pemetrexed disodium was given to the nude mice bearing lung adenocarcinoma cell line A549 cells at different times in the day and night according to the theory of chronopharmacology can enhance the curative effect and reduce side-effects. Methods 1×10⁷ A549 cells in exponential phase of growth were vaccinated in the good health body of Balb/c nude mice by subcutaneous injection(injection under the skin).When tumor volume reached 0.5~1.5 cm3，tumor-burdened nude mice was divided randomly into four groups and each group has 5 mice，Three groups were randomly appointed to 7 hour group，15 hour group and 23 hour group according to the three time of injection of 07:00， 15:00，23:00， for abdominal administration.The remainder group was left for blank controlled group，for abdominal the same volume of saline.The tumor tissue was measured from major axis to minimum width once a week,and calculated the volume for drawing the growth curve.As the tumor,tissue growing to meet the volume of 0.5~1.5cm³,intraperritoneal injection with pemetrexed disodium was performed at 150 mg/kg (total dose，600 mg) in 200 μl PBS i.p.for 4 consecutive days (days 0~3).Meanwhile,The observiation was carried out as the following:the appetite,the movement,and the mental state of nude mouse,as well as the tumor size.The weight of the nude mice was measured once a week for drawing the chart.The tumor weight of the nude mice was calculated for counting the tumor inhibition rate.qRT-PCR was applied to detect the expression of the TS mRNA and TP mRNA in the tumor tissue. Results Pemetrexed for lung adenocarcinoma nude mice transplant tumor has good curative effect，7 h group tumour inhibition rate was the highest（P=0.000），the slowest tumor growth（P=0.032），the more nude mice weight（P=0.041）relative express level of TS mRNA of 7 h group tumor tissue was the lowest ，however，TP mRNA was the highest.Difference was statistically significant（P<0.05）. Conclusion Pemetrexed for lung adenocarcinoma nude mice transplant tumor has apparent inhibition and efficacy and side effects appears hour rhythm changes，the curative effect of 7 h group was the best.it looks on TS mRNA and TPmRNA as side effects and curative effect biological marker of pemetrexed，it provideds us reference for rationalization and individualized clinical application of pemetrexed.