The effects of precursors, such as coenzyme Q₁₀, p -hydroxybenzoic acid, solanesol, L-tyrosine, L-phenylalanine and methionine, on the dry weight of suspension cell, Q₁₀ production and intracellular Q₁₀ content in tobacco NC 89 were studied with cell culture method. The results showed that: the addition of precursors could increase cell's dry weight and intracellular Q₁₀ content to a certain extent, especially p -hydroxybenzoic acid and methionine had significant effects on cell's dry weight. The coactions of either p -hydroxybenzoic acid or L-phenylalanine, together with methionine extremely significantly affected Q₁₀content. The production of Q₁₀ changed along with cell's dry weight and intracellular Q₁₀ content. Therefore, it was allowed to apply selected precursors of proper concentration stepwisely at different cell culture phases.