A series of polymeric hollow latex particles with various encapsulation ratios of intermediate layers to cores were prepared via the alkali swelling method.Then,the products were analyzed in terms of the size and the viscosity and were characterized by means of SEM,TEM and UV- Vis spectrophotometry,and the effects of the encapsulation ratio on the morphology and opacity ability of the products were investigated.The results show that (1) when the encapsulation ratio increases from 6 to 10,the swelling degree of the hollow latex particles decrea-ses,the swelling strength gradually increases,and the opacity ability first increases and then decreases; (2) when the encapsulation ratio is 6 and 7 ,the hollow latex particles are of rough surfaces with higher swelling degrees,bigger cavities and thinner intermediate layers as well as some collapse and rupture; (3) when the encapsulation ratio is 9 and 10,the hollow latex particles are of smooth surfaces with lower swelling degrees,smaller cavities,thicker intermediate layers and with almost no collapse and rupture; and (4) when the encapsulation ratio is 8,the hollow latex particles possess a moderate swelling and achieve the best opacity ability.