The main aim of runoff harvesting in semi-arid area is to lighten soil and water loss, solve the problem of watering people and domestic animals, develop courtyard economy, prevent drought and keep a full stand of seedings, irrigate supplementarily(SI) fruit trees, vegetables in greenhouse and solar radiation greenhouse, irrigate supplementarily field crops. Different use measures of harvested runoff have much different benefit. According to output value of water pur ton(OVPt). The results of benefits of every water use measures show: If soil water capacity is lower than 11 percent, water providing sowing technology can keep a full stand of seedings used 15～45m³/ha water. Water providing dibble technology can keep a full stand of seedings of corn or other thinly scattered crops used 1～1.5kg water pur spot or 30～45m³/ha water. Through SI, OVPt of fruit trees can reach 40 Yuan,and that of vegetables cultivated in solar radiation greenhouse can reach 72 Yuan, vegetables cultivated in greenhouse 15 Yuan, the OVPt of field crops are all lower than 11 Yuan. But most of the area which is suitable for runoff harvesting is far from household, it is difficult to produce fruit and vegetables in this area, cereals can be produced only. Although benefit of fields crops cultivated with SI is not goods enough, if SI is used in a big area, the problem of sufficient goods and adequate clothing can be solved stablely.