Abstract: Poly-surfactant to fit the characteristics of the fracture-cave type carbonate reservoirs in Tahe oilfield is selected. The experimental results showed that the oil-water interfacial tension reaches 10^-2 mN/m when the poly-surfactant is in the lower concentration of 0.035%. The interfacial tension can be lower than 10^-2mN/m at high temperature and high salt reservoir conditions. By using poly-surfactant, the crude oil viscosity can be reduced to 94% above, and the interfacial tension maintained within 10^-2 mN/m after heated for 30 days. The simulated crack experiment showed that salted water cannot displace oil when the gap less than 4.0mm, but the poly-surfactant water can displace oil substantially when the gap was 1.16mm. The combination of suture holes simulation experiments showed that the greater the crack width is, the more the simulated oil out of the hole is.