This paper discusses the technology of low sugar preserved watermelon using the fresh watermelon as the raw materials. The results showed that the hardening effect is better by treated with 0.3% sodium sulfite for 5 h. Microwave or vacuum was adopted as the best process for sugar osmosis of the Low-sugar preserved watermelon and the optimal formula of technology is as follows: sugar is 30%; the starch syrup is 40 %; the tagatose is 0.02%; the citric acid is 0.2%; the drying temperature is 60℃ and the time is 16~20h.