The invention discloses a method for preparing a rough sodium tungstate solution by decomposing wolframite concentrate at a high temperature and high pressure through low alkaline. The method comprises the following steps that wolframite concentrate powder and water are mixed to form wolframite pulp, sodium hydroxide, trisodium phosphate and sodium nitrate are sequentially added into the wolframite pulp to mix the pulp, mixed wolframite pulp is formed and decomposed, the decomposing temperature is 192 DEG C-210 DEG C, pressure is 0.8 MPa-1.0 MPa, after decomposing, diluting, filter pressing and washing are carried out, a filtrate is taken, and the rough sodium tungstate solution is obtained, wherein the adding amount of the sodium hydroxide is 1.4-1.6 times the theoretical amount of the weight of tungsten trioxide in the wolframite concentrate powder. The method has the beneficial effects that the amount of the alkaline is reduced, and the tungsten decomposing rate of the wolframite concentrate is increased.