The invention relates to a soil wet screening device and method and belongs to the technical field of geotechnical tests. The soil wet screening device comprises a top cover, a plurality of sieve trays and a chassis. The top cover and the corresponding sieve tray are assembled through threads, every two adjacent sieve trays are assembled through threads, and the corresponding sieve tray and the chassis are assembled through threads, so that a single screening unit is formed. An opening is formed in the upper end of the top cover, a connection frame is fixedly arranged at the opening, and a semitransparent film is embedded in the lower end of the top cover. The sieve trays are sequentially arranged between the chassis and the top cover according to the order that mesh sizes are gradually increased from bottom to top. An opening is formed in the upper end of each sieve tray, and a screen cloth is embedded in the opening in the bottom end of each sieve tray. An opening is formed in the upper end of the chassis, and the opening of the bottom end of the chassis is sealed. The single screening units can be connected into a multiple screening unit through connecting pieces, screws and nuts. During wet screening, samples are poured into the sieve tray in the maximum mesh size, the top cover is screwed up, and then the whole device is immersed in water to conduct screening. According to sample grouping situations and test requirements, various wet screening functions can be achieved through the device and method; besides, the samples are effectively prevented from overflowing and running off, test efficiency is high, operation is convenient and fast, and result accuracy is good.