The formula of indexing electron diffraction patterns from tilted crystal is as follows, hkl=xy0Γ(θ)Γ(ω0-ω)Γ(θ0)P-1H, where θ,ω are rotating angles and θ0,ω0 primary ones. A program applicable to all the crystal Systems has been worked out. This method is simpler and faster than that of stereographic projection.