The purpose of the study was to develop an assessment scale for science activity videos that can be used to determine qualified science activity videos that can fulfill the objectives of activity based science education, help teachers to evaluate any science activity videos and decide whether to include into science learning process. The subjects for the study comprised a group of 47 science teacher candidates who were at their junior year in state university. In scope of a must course, each science teacher candidates were assigned an objective from K12 science curricula. Then, they were expected to seek for a science activity that can be conducted and recorded in form of 3-5 minutes long science activity video. The teacher candidates were asked to evaluate science activity videos developed by themselves for their classes, schools, and individual use through a scale to assess science activity videos. Science teacher candidates were given three weeks to complete the evaluation form, after which time they were returned to the researchers for assessment. The data from the scale were analyzed through descriptive and item analysis in terms of frequency, reliability and factor routines. The body of the scale covers 20 evaluation criteria in four major categories as technical features, narrator features, activity process, and security issues. The developed evaluation scale for science activity videos will provide a useful logical framework to help educators and/or trainers to identify adequate science activities in point of quality for their instructional purposes.