Lightning counting data obtained at Xining in 1997 and at Huzhu in 1998 with an SD type counter are analyzed.It is found that the counter can cover an area as large as 40 km in diameter even in the mountainous districts.It is also found that for hail suppression seeding to a thunderstorm lightning flash rate should be ≥40 times/(5min) if the thunderstorm is moving from a mountain area to a plain area and be ≥30 times/(5min) if the thunderstorm is moving from a plain area to a mountain area.The rising gradient of flash rate,if larger than 10 times/(5min),is also indicative of the opportunity for hail suppression.It is concluded that a simple and economic lightning counter is a very useful device for identifying thundercloud and hail producing cloud and for making a decision on the opportunity of hail suppression especially when a weather radar is not available for hail suppression.