Abstract: A number of meteorological factors influencing surface air temperature lapse rate over mountainous regions are discussed.Calculations are made concerning the lapse rate both over the areas and in the free atmosphere and the comparison of the differences and the relations between them.In addition, the types of annual variations of the lapse rate and their distribution are presented.In China, they can be roughly divided into six types (summer peak, winter peak, double peaks in spring and autumn, spring peak, autumn peak, and, no marked annual variation).Of these six types, the summer peak type, which is related closely basic feature of the monsoon climate, is the most widely distributed, extending over most of the mountainous regions of China except for a few plateau areas.Finaly, the general distributions over China of the rate under study are graphically shown and analysed qualitatively.From these analyses, it is found, the decrease of surface air temperature along the mountain slopes is greater in winter than in summer, over plateau regions than over hills, in lower latitudes than in higher latitudes, over dry regions than over the interior and on the lee side than on the windward side of the mountains.