Introduction: Learning based on solving problem (PBL) , a useful and replacement educational method was against current and traditional methods and its particulars is teaching solve of problem and skills of learning, increase motivation and maintaining and keeping data. Educational directors and in charges are even in seeking finding of methods for more efficient of educational methods.

Materials: This study was done as half experimental on 40 students of Medical training in Army University of Medical Sciences in 20015 .At first, method PBL in educational workshop taught to students in an educational workshop and 2 alike educational syllabus and the same level were selected according to method PBL

  In 1^st. stage, students were divided as random and in 2^nd stage as Stratified Radon sampling from view of average to 5-person groups and educational syllabuses were taught according to method PBL.

In any two stages, instructors and time and facilities, similar used were designed. Assessment of students by Pretest-Post test and opinion-assessment papers were done and results with software SPSS.16 and statistical test event were statistically analyzed.

Results: in comparison rate of coefficient of hardness and volume of material under learning in two education stages, a meaningful statistical difference was not seen from view of students. (P>0.05) from one hand, comparison of average of results of previous test in 1^st. stage with 2^nd stage of education doesn't show a meaningful statistical difference. (P>0.05)

Average of results of post test in 1^st and 2^nd stages of education of assessment that was compared orderly with results of pretest in 1^st and 2^nd educational stages and meaningful statistical difference was reported. P=0.00

Comparison of average of results of post test in 1^st educational stage with average of results of post test in 2^nd educational stage shows a meaningful statistical difference. (P<0.05)

Conclusion: Becoming more competent and increasing rate of learning   in educational methods was noted by directors and educational in charges. Whereas, attendance and performance correct effect of Tutor in progressing of directing small groups in method PBL has a fundamental role, attending of active educational students next to the weaker students are effective for solving of problems and learning method. It is proposed, instructors intervene in forming of small groups in method PBL and with resembling groups, help to better execution if this method