Anneal isolating objects with good reactivity for silica steel sheet and using method thereof

Disclosed is an annealing separator for producing grain-oriented silicon steel sheet used, which contains one or more compounds selected from the formula: [Mg wherein MM0.01≤X≤0.40; X = X1 + X2. Such a lower melting point and having a higher reactivity to the annealing separator is applied after decarburization annealing the steel strip, which improves the performance of the glass film, especially having a uniform film appearance and good sealing effect, and magnetic properties.