Purpose of this study was to compare the relative effectiveness of constructive approach "focusing 5E Learning Approach" and traditional textbook methods with an intention of identifying most appropriate method of teaching biology at secondary school level to enhance the conceptual understanding of biology among them. To guide this study hypothesis were stated and tested at 0.05 (significance level). The design of the study was pre-test post-test experimental design, sample was consisted of 60 biology students from Govt. Boys High School of Kahuta Rawalpindi and an equal number of students were randomly assigned to control and experimental groups. Experimental group was treated through 5E Learning Approach. Same test was administered as pre-test and post-test and scores were compared using t-test. It was concluded; constructive approach proved to be more effective for teaching biology at secondary level and students treated through constructive approach showed more interest and better understanding of the concepts.