Multiphase flows are very important in industrial application. In present study, the force schemes in the pseudopotential LBM for two-phase flows have been compared in detail and the force schemes include Shan-Chen, EDM, MED, and Guo's schemes. Numerical simulations confirm that all four schemes are consistent with the Laplace law. For Shan-Chen scheme, the smaller.. is, the smaller the surface tension is. However, for other schemes, tau has no effect on surface tension. When 0.6 < tau <= 1, the achieved density ratio will reduce as tau reduces. During this range of tau, the maximum density ratio of EDM scheme will be greater than that of other schemes. For a constant T, the curves of the maximum spurious currents (u') has a minimum value which is corresponding to tau' except for EDM schemes. In the region of tau' < tau <= 1, u' will reduce as tau decreases. On the other hand, in the area of tau <= tau', u' will increase as tau decreases. However, for EDM scheme, u' will increase as tau increases.