The invention discloses a method for manufacturing a polycrystalline silicon ingot casting fused quartz crucible without spraying. The method comprises the following steps: grinding high-purity fused quartz raw material by a ball mill so as to conduct wet pelleting, stirring slurry comprehensively, then adding powder high-purity fused quartz raw material and stirring uniformly, subsequently injecting the mixture into a gypsum mold to fully dewatering molding, and de-molding; drying a de-molded green body under the temperature below 180 DEG C so as to obtain a blank; grinding, cleaning and pre-processing the blank; spraying silicon nitride coating being 0.2-0.7mm on the inner surface of the blank; and rotating and sintering the blank sprayed with the silicon nitride coating for 14-24h in arotary kiln under a temperature being 1000-1300 DEG C. According to the manufacturing method, compared with the prior art, the production period is shortened, the production process is simplified, the energy consumption is reduced greatly, and the production efficiency, the yield and the economical benefits of enterprises are improved.