Abstract: This paper experimentally studied the thermal performances of the flat-plate solar water heater and the all-glass vacuum tube solar water heater. The effects of the placement of the collector (southern facade horizontal row and vertical row), and the circulation type (natural circulation and forced circulation) on the system thermal performance and the tank stratification were achieved. The results showed that for the southern facade balcony-style all-glass vacuum tube solar water heaters, the water circulation was faster when the collector was placed horizontally, and the thermal efficiency increased by 12%. For the southern facade balcony flat-plate type solar water heater, when the system run under natural circulation, whether the collector was placed horizontally or vertically, liquid circulation is not smooth，and the thermal efficiency of the system was less than 30%. Forced circulation could effectively improve the circulation. The average inlet and outlet temperatures kept stable, and the system efficiency was 63% approximately when the system run under forced circulation.