We search for CP violation in the decay D+→K0SK+ using a data sample with an integrated luminosity of 977 fb−1 collected with the Belle detector at the KEKB e + e − asymmetric-energy collider. No CP violation has been observed and the CP asymmetry in D+→K0SK+ decay is measured to be (−0.25 ± 0.28 ± 0.14)%, which is the most sensitive measurement to date. After subtracting CP violation due to K0−K¯¯¯¯¯0 mixing, the CP asymmetry in D+→K¯¯¯¯¯0K+ decay is found to be (+0.08 ± 0.28 ± 0.14)%.