AIM: To discuss the relationship between onset of peptic ulcer (PU) and meteorological factors (MFs).METHODS: A total of 24 252 Patients were found with active PU in 104 121 samples of gastroscoic examination from 17 hospitals in Nanning from 1992 to 1997. The detectable rate of PU (DRPU) was calculated every month,every ten days and every five days. An analysis of DRPU and MFs was made in the same period of the year. A forecast model based on MFs of the previous month was established. The real and forecast values were tested and verified.RESULTS: During the 6 years, the DRPU from November to April was 24.4 -28.8%. The peak value (28.8%)was in January. The DRPU from May to October was 20.0 -22.6%, with its low peak (20.0%) in June. The DRPU decreased from winter and spring to summer and autumn (P ＜ 0.005). The correlated coefficient between DRPU and average temperature value was -0.8704,-0.6624, -0.5384 for one month, ten days, five days respectively (P ＜ 0.01). The correlated coefficient between DRPU and average highest temperature value was -0.8000, -0.6470,-0.5167 respectively (P ＜0.01). The correlated coefficient between DRPU and average lowest temperature value was -0.8091, -0.6617, -0.5384 respectively (P ＜0.01). The correlated coefficient between DRPU and average dew point temperature was -0.7812,-0.6246, -0.4936 respectively (P ＜0.01). The correlated coefficient between DRPU and average air pressure value was 0.7320, 0.5777, 0.4579 respectively (P ＜0.01). The average temperature, average highest and lowest temperature, average air pressure and average dew point temperature value of the previous month, ten days and five days could forecast the onset of PU, with its real and forecast values corresponding to 71.8%, 67.9% and 66.6% respectively.CONCLUSION: DRPU is closely related with the average temperature, average highest and lowest temperature,average air pressure and average dew point temperature of each month, every ten days and every five days for the same period. When MFs are changed, the human body produces a series of stress actions. A long-term and median-term based medical meteorological forecast of the onset of PU can be made more accurately according to this.