In-service education programs have provided the professional development level of companies' employers, in the high quality form. The applying of in-service education programs has been a key component of professional development process for staff agro-industry Company. The study is utilized experimental Solomon four group designs to determine the impact of in-service education programs on agro-industry company staffs' professional development level. Results demonstrated that subjects learned from the educational programs and achieved higher level of professional development and demonstrated that there is significant difference among professional development level of clients. Post hoc analysis demonstrated that participants in treatment groups (E &C2) answered significantly greater numbers of questions correctly on the posttest exams and achieved significantly higher level of professional development than the control groups (C1 & C3) and there was significant different between professional development level of participants in pretest and posttest in E group but there was no significant different between professional development level of participants in pretest and posttest in C1 group.[A. N, Noorivandi. Analysis the Impact of In-Service Education on Professional Development of Employers, by Using Solomon Four Group Design, in Agro-Industry Company. International Journal of Agricultural Science, Research and Technology, 2011; 1(1):13-16].