The aim of this study is to investigate the efficiency of using Cooperative learning strategies in writing expression in the preparatory level, from the answers to the following questions: 1. What are the desired aims of teaching writing expression in preparatory levels? 2. What are the techniques of Cooperative learning strategies that go with learning writing expression? 3. What is the effect of using Cooperative learning strategies in achieving the aims of writing expression in students of this level? 4. Are there any statistically significant differences between the means score of the experimental groups of students in the post-test due to the factor of sex? The sample of this study contains about (120) pupils, about (60) are boys and girls in the two experimental groups and about (60) boys and girls in the two control groups The important result of this study is: 1. There were statistically significant differences (p>0.001) between experimental group, of students who studied the writing expression within the Cooperative learning strategies and the control group, of students who studied the writing expression within the classical method, thought in favor of the experimental group. 2. There were statistically significant differences (p>0.05) between experimental group for male and experimental group for female in favor of the experimental group for female. 3. There were statistically significant differences (p>0.001) between the means of two experimental groups based on the interaction effects between Cooperative learning strategies and sex in the student performance in the writing expression.