[Aim]  To assess the effect of intercropping maize and legumes on the population dynamics and distribution of Monolepta hieroglyphica adults in Jilin Province. [Methods]  The field netting method was employed to compare the effects of nine planting patterns on the abundance, body length, body weight, and distribution, of emerged adults. [Results]  The emergence of M. hieroglyphica adults followed a unimodal curve in Jilin Province, with peak emergence occurring from mid to late July. The proportion of female adults was initially less than 35%, increasing to over 75% in the late emergence period. Females had a significantly greater body length and weight than males (P<0.05). Adults were markedly longer and heavier in August than in July (P<0.05). Monocultures of soybeans, or mung beans, did not reduce body length or weight, whereas intercropping with legumes significantly reduced female body length and weight (P<0.05). [Conclusion]  In maize fields in Jilin Province, adult M. hieroglyphica began to emerge in early July, reached peak abundance in mid-late July, and then gradually declined. Female adults were significantly longer and heavier than males. Both body length and weight were closely associated with emergence time, with females that emerged later being significantly longer, and heavier, than those that emerged earlier. Intercropping maize with legumes can reduce the body length and weight of adult female M. hieroglyphica.