The purpose of this study is to investigate the effects of Algorithm-based mathematic activities to young children’s mathematical problem solving ability. For this purpose, a total of 42 students (experimental group 21, comparative group 21) of five-year old children at I kindergarten located in D city were studied for 6 weeks. The experiment group performed the mathematics activities through the algorithm-based, and the comparative group performed the mathematics activities in the Nuri course based on life topic. The results of this study is that, in the mathematical problem solving ability, there was a significant difference between the two groups in number, operation, algebra, geometry, measurement, and statistics. The result of this study suggests that a Algorithm-based mathematical activities may result in enhanced ability of solving problem and it is expected that it can act as basic data for the development of mathematics education program.