In order to master the dynamic changes of cucumber fruit growth in solar greenhouse and its relationship with meteorological elements of greenhouse, continuous no damage dynamic monitoring for transverse diameter of Cucumber fruit collected by every 10 min were carried out by the crop growth monitoring instrument, air temperature, air relative humidity, solar radiation and other factors in the greenhouse were also continuous observed by micro climate observing system. Studies have shown that cucumber fruit diameter hourly increment is most at 17:00 or 18:00 in the fair-weather, but least at about 11:00, with a sensible diurnal variation; in the cloudy weather, the growth law of cucumber fruit diameter is similar to which in the fair-weather; the hour increment has a no apparent diurnal variation in the overcast weather; in the overcast to clear weather, there was a noticeable transformation in the diurnal variation of cucumber fruit diameter hourly increment, the diurnal peak value usually appears at 17:00 or 18:00, but before and after noon rebound phenomenon could occurs obviously. The good correlation with the Cucumber fruit diameter hourly increment should be in the sequence below: the average temperature four hours before, the average relative humidity four hours before and the average solar radiation five hours before; The significantly correlation with the Cucumber fruit diameter daily increment should be in the sequence below: the daily minimum temperature that day, the daily average temperature the day before, the daily average relative humidity the day before, the daily average radiation the day before, and daily temperature range the day before.