The transmission system is a place of electrical power distribution from the center of the plant to the mains station or from the parent's garage to the other mains booths. The transmission system is not detached from the good ground so that the transmission system is spared from lightning strikes so that there is no spark that endangers the transmission system. The good ground is to get the smaller value, to get a good value, then not regardless of the climate in the area. Indonesia is a tropical region, in Indonesia there are two seasons, namely the rainy season and the dry season. This research is to know the resistance value of high voltage air channel 150 KV Bantul-Klaten in the rainy season and dry season. In the rainy season the value of ground resistance in good condition is due to the humidity and moisture content in the soil is still making large electrical power. In the dry season the resistance value of the ground is in poor condition or large resistance value, high ground resistance value due to soil type and moisture content and small humidity so as to make the soil hard and power supply Smaller.