a manufacturing method of oriented silicon steel with magnetic induction b8 of not less than 1 . 88 t , comprising the following steps : 1 ) smelting and continuous casting to obtain a slab , wherein the content of n is controlled at 0 . 002 - 0 . 014 wt % in the smelting stage ; 2 ) hot - rolling ; 3 ) cold - rolling ; 4 ) decarbonizing and annealing ; 5 ) nitriding treatment , wherein infiltrated nitrogen content d is controlled to satisfy the formula : 328 − 0 . 14a − 0 . 85b − 2 . 33c ≦ d ≦ 362 − 0 . 16a − 0 . 94b − 2 . 57c , wherein a is the content of als in the smelting step , with the unit of ppm ; b is the content of n element , with the unit of ppm ; and c is primary grains size , with the unit of μm ; 6 ) coating a steel &# 39 ; s surfaces with a magnesium oxide layer and annealing ; and 7 ) applying an insulating coating .