The present invention provides a robot hand with weighting device including a holding part, a transmission valve, a carrier plate and a weighting device. The holding part is installed on the transmission valve to receive the power conveyed from the transmission valve. The weighting device is provided between the carrier plate and the transmission valve. The weighting device comprises a sensor base, an elastic part and a touching part. The sensor base is fixed on the carrier plate. A data transmission port is provided outside the sensor base. The data transmission port connects with a display device. The elastic part is mounted inside the sensor base. A resistance extensometer bridge is stuck on the elastic part. The touching part is set on the top of the elastic part. The touching part connects with the transmission valve. The robot hand with weighting device outputs the weight information in the process of carrying product due to the weighting device.