Abstract: According to energy conservation principle and the measurement principle of condensed mode to steam quality, a kind of measurement method of energy conservation condensed mode to steam quality is suggested, and the steam quality meter of energy conservation condensed mode is developed by the measurement method. Quantitative analysis for metrical precision of the meter is discussed, and its result shows that the metrical precision of the meter reaches 98%; the match model for enhancing metrical precision is suggested. An online installation project of the meter is constituted, the online experiment of the meter shows that this meter possesses the character of accuracy and practicality of online measurement.