The purpose of this study is to develop a POE (predict observe explain) based mathematical module on the subject matter of a straight-line equation. It is also to see the response of educators and learners to POE (Predict Observe Explain) based mathematics module on the basic material of straight line equation. This research uses Research & Development. The design validation stage involves 9 subjects namely three material experts, three media experts and three linguists to assess the material feasibility, the design of math modules and the feasibility of Indonesian language is good and correct. The pilot phase is done through 2 stages small group trial and field trials. Based on the validation results of the expert material obtained an average score of 3.34 with valid criteria, for the media expert to obtain an average score of 3.52 with valid criteria while for the linguist get an average score of 3.33 with valid criteria. In the test phase of response 2 educators got an average score of 3.37 with very interesting criteria. As for the response of learners on small group trial obtained an average score of 3.05 with interesting criteria and on field trials obtained an average score of 3.33 with very interesting criteria so that the math module is feasible to be used as teaching materials.