The invention relates to a pesticide adjuvant and applications thereof. The pesticide adjuvant is characterized by comprising the following ingredients by mass percentage: 90 to 100 percent of pine-stump light oil and 0 to 10 percent of cosolvent, wherein the cosolvent is at least one of n-butyl alcohol, isobutyl alcohol, N-methylpyrrolidone, N-hydroxyethylpyrrolidone and methyl salicylate. The pesticide adjuvant is applicable to various pesticides, and particularly applicable to missible oil, oiling agent, oil suspension solvent, suspension emulsion, micro-emulsion, aqueous emulsion and ultra-low volume concentrate, and also can be used as barrel pesticide mixing assistant agent; and the pesticide adjuvant is applicable to preparation of ingredients of pesticides such as insecticide, acaricide, bactericide, herbicide, plant growth regulator and the like. The pesticide adjuvant and the barrel-mixing agent have strong dissolving power, is environment-friendly, have synergy effect on agents, wide source and moderate use cost, and is the ideal choice substituting for triphenyl organic solvents.