The present invention relates to an algae removal composition which contains percarbonate for offering an environmentally friendly and effective algae removing agent. The percarbonate sodium percarbonate (2Na2CO3·3H2O2) or potassium percarbonate (2K2CO3·H2O2).COPYRIGHT KIPO 2014[Reference numerals] (AA,BB) removal rate of floating material (%)(CC) Example 1(DD) Example 2(EE) Example 3본 발명은 친환경적이며 효과적인 조류 제거제를 제공하기 위하여, 과탄산염을 포함하는 조류 제거용 조성물을 제공한다.