Solution treated Ti-2.5Cu alloy was aged under a compressive stress of ~200 MPa. TEM investigations show that three variants of precipitated Ti2Cu plates are observed in conventionally aged samples without compressive stress. However, in the stress-aged samples, for most grains, one or two variants of Ti2Cu plates could be observed, which indicate the variant selection effect of precipitated Ti2Cu plates resulting from external compressive elastic stress. Lower yield strength and higher elongation is observed during subsequent tensile tests due to the variant selection effect.