Abstract: Morwet D-425 and Witconol NP-100 were put into 20% thiram+carbofuran flowable concentrate for seed coating (FSC) and 30% carbendazim+thiram+carbofuran FSC instead of routine emulsifier at a series of concentrations. Viscosity, bleeding, particle aggregation, unrecoverable sedimentation and particle diameter were tested. The mass fraction of Morwet D-425 and Witconol NP-100 was determined as 3.0% and 1.0% in 20% thiram+carbofuran FSC or 4.0% and 1.0% in 30% carbendazim+ thiram+ carbofuran FSC. Test results showed that viscosity was 390 and 510 mPa·s after one day stored. During the storage of 30 d in room temperature and 14 d in (54±2)℃, particle aggregated no more than 10%, and no unrecoverable sedimentation has been detected. There was 5% and 9% water in the two new formulations, 20 percent less than that in the routine formulations, bleeded respectively after stored in (54±2)℃ heat box while less than 1% liquid bleeded in room temperature. FSC samples in the presence of Morwet D-425 and Witconol NP-100 or routine surfactant were tested by laser particle size analyser after milling of 0.5,1.0,1.5 and 2.0 h. The finding is that after 1.5 h milling, the mean volume diameter came to be 1.85 and 1.91 μm for new formulations but more than 2.0 μm for routine formulations 2.0 h later.