The utility model discloses a concrete laitance layer thickness tester, including control cabinet, board, movable cross beam, survey test panel, concrete container and scale etc, movable cross beam slides from top to bottom to adorn and connects at the board, survey test panel dress connects has pressure sensor at the movable cross beam parallel connection, and survey test panel goes up evenly distributed has a plurality of confession laitances to flow through the through -hole of the thick aggregate of separation, the concrete container is located surveys the test panel below, drive to survey test panel to the concrete container in through movable cross beam to drop to thick aggregate layer top in the laitance layer, survey the pressure variation that test panel receives in order judging its position through pressure sensor, and record laitance layer thickness through the scale. The utility model discloses the thickness of ability direct measurement laitance layer can reduce tester's subjective influence when experimental, provide accurate reliable tentation data, and simply easily operation of test method, has important meaning to the admixture performance of concrete and the research of concrete construction performance.