Ni/CrAl coating was prepared on T91 steel by composite electrodeposition process. The relationship between CrAl content in coating and stirring intensity, currnt density, pH as well as temperatures were studied in Watts solution. The optimum process of composite electrodeposition of Ni/CrAl composite coating was obtained as follows: current density was 2.5~4.5 A/dm2, the temperature was held at 30℃ and pH was 4~4.5. According to this electrodeposition process high content CrAl coating was obtained. The mechanism of electrodepostion affected by process parameter was discussed in brief.