With finite element model of Ansys software,the model of reinforced concrete beam is established under monotonous loads.At the basic of cracking and ultimate loads between Ansys calculate value and experimental ones,the stress changing of Carbon Fiber Reinforced Plastic(CFRP) and concrete are analyzed at different loads.The cracking and development rules are also simulated.The results show that the maximum error of Ansys calculate values and experimental ones is in 10.2%,function of the CFRP conform to experimental ones,the distribution and development of crack also accord with experimental ones.