The raingauge and weir for measurement were set up in a area 0.8 hectare of small watershed with thorny bamboo plantation of the comprehensive experimental zone for soil and water conservation, National Pingtung University. All the data of rainfall and runoff discharge were collected to estimate the hydrograph during rainy season from 2018 to 2019. The non-dimension’s and Horner’s rainfall intensity formula were adopt to predict maximum peak flow with recurrence interval in two years, had shown 0.054 cms and 0.078 cms, respectively. To contrast the two predictions with measured maximum peak flow could find non-dimension’s that was similar to practical condition. The runoff coefficient of bamboo plantation were about 0.20~0.45.