Application of system form is very effective to continuous horizontal or vertical walls of the apartment housing. Though the system forms that are used in the construction field have the advantage of concrete quality improvement and increasing number of usages, there are some problems in reaching early planning scheduling goal due to schedule delay and low productivity. This study is initiated to solve the problem and suggest some improvements searching for reasons that diminish the productivity. A case study was done in apartment construction field where system form was used and the productivity is analyzed by work sampling. Finally, productivity improvements for assembly of the form, internal form and external form are suggested, respectively.