In order to ensure the safety of mountain water transmission network, the diversion type energy dissipation device was designed. The device was composed of an upper shell, an energy dissipation cavity and a lower shell, which was provided with an inlet end and an outlet end. The energy dissipation cavity was provided with an evenly spaced energy dissipation plate and a diversion hole. Fluent numerical simulation and experiments were used to verify the test method. Three inlet velocity rates, three diversion aperture ratios and the presence or absence of diversion plates were set to carry out all-factor tests, and energy dissipation rate comparison tests were carried out on the diameters of two diversion holes. The results showed that under the guarantee of overflow capacity, the inlet velocity and diversion aperture both played a leading role in energy dissipation rate. The larger the inlet velocity was, the larger the flow rate was, the better the energy dissipation rate would be. The energy dissipation rate was negatively correlated with the diversion aperture, and the smaller the diversion aperture was, the better the energy dissipation was. When the base aperture was the same, in order to satisfy the overflow capacity at the same time and ensure the dissipation of energy to achieve a better effect, it was recommended to choose the diversion aperture ratio unchanged arrangement. When the inlet velocity was 1.0m/s, the local head loss accounts was 96.3% of the total head loss, so when calculating the total head loss, frictional head loss can be ignored.When inlet velocity was less than 4.0m/s, when choosing not to install the deflector, it can be up to 4.0m/s, the presence of deflector dissipation was flat, when it was more than 5.0m/s, the effect was better when choosing to install deflector energy dissipation.