This research is a qualitative research, which is describe the ability of cadets to solve routine and non-routine problems of trigonometry material in applied mathematics subject. Competence of learning achievement in applied mathematics course required cadets to be able to solve mathematical problems related to trigonometry. An analysis of this ability was needed as an illustration of lecturers in developing lesson plan which is more effective and efficient. The population of this study was cadets of the ship engineering study program academic year 2018/2019 and the sample of study was three cadets chosen by random. The technique of collecting the data by using the results test of the cadets. The results of the study shown that the ability of cadets to understand problem and apply the concepts to solve routine problem was good, although not all of the information was written in their answers. The cadets’ ability to compile and carry out a plan of routine problems was quite good, even though they immediately wrote the formula to solve the problem.The ability of cadets to understand non-routine problem was not good, due to, cadets have not been able to know the additional information that must be extracted from the problem.