FRP strengthening technique provides a promising alternative for masonry structures. This paper presents research results of quasi-static tests investigating the in-plane mechanical behavior of RC-brick masonry walls with opening strengthened with basalt fiber reinforced polymer (BFRP). Two half scale RC-brick walls were constructed, one without any strengthening scheme served as the reference specimen, another one was directly strengthened with BFRP in mixed strengthening configuration. All specimens were tested under low frequency cyclic loading. BFRP can effectively improve the lateral strength of the wall by a factor of 0.16, and the improvement in the lateral deformation capacity was much significant. The seismic performance of the composite wall strengthened with BFRP can exceed the unreinforced reference, which verifies the effectiveness of BFRP strengthening technique to strengthening RC-brick composite masonry structures in seismically endangered regions.