Based on the heat integration principle and temperature-enthalpy graph, a co-current multi-effect drying model is established. Being proved by the composite curve of the temperature-enthalpy graph, pressure of each effect is designed in same pressure drop mode. Numbers of effect from 1 to 5 are simulated by iterative method, while the h is 0.7, 0.8 and 1. The results indicate that the co-current multi-effect drying can reduce the use of fresh vapor by at least 33% .