: Problems that occur in learning biology class X SMAN 4 Palangkaraya was oftened using cooperative approach, but does not give optimal results which marked with bold argue that few students are less active , it was showed the skills assessment of performance students were not familiar in practice, so that mastery learning does not reach a minimum completeness criteria. This study aims to improve the skill of performance students through the approach of Problem Posing . This study using The Principles of Classroom Action research . The results showed that the most percentage of performance skills in Cycle I is enough category, in Cycle II is good category the most, and very good category most placed in evaluation results. Application of Problem Posing approach can improve performance skills , mastery learning up to 80.3 % , and students show positive respond to learning activities of Problem Posing approach.