Abstract: The main pest species and occurrence in spring watermelon greenhouse in Daxing district, Beijing are investigated to provide information for pest control and prediction. Field investigation and yellow stick cards were used to survey the pest species and dynamics in watermelon greenhouse in Daxing district, Beijing for two consecutive years. The results showed that the main pests in spring watermelon greenhouse were polyphagous pests: red spider mites, thrips and aphids. The pests trapped by yellow stick cards with the largest number were thrips, followed by aphids, so they were the dominant pests, other pests counted for less than 0.5% . The dominant pests infested watermelon leaves were also polyphagous pests: red spider mites and wingless aphids, which accounted for more than 58.07% and 6.35% for the two consecutive years, respectively. The occurrence peak of wingless aphids (early and mid May) was earlier than that of winged aphids (late May) and the aphid population decreased after mid June. The thrips trapped by yellow stick cards reached the population peak in June and remained until the plants were uprooted. The thrips infested watermelon flowers reached the peak in mid June, then decreased in July as the number of flowers decreased. In 2014, the red spider mites reached the population peak in early June, and then continued to decline. In 2015, the occurrence of red spider mites was slightly aggravated and the time was advanced. In May, the mites occurred slightly. In June, the mite number increased quickly, reached the peak in mid June, and remained until the plants were uprooted. For those polyphagous pests, the aphids should be controlled mainly in May and June, while the thrips and red spider mites should be control mainly in June and July.