Abstract: The study of second language processing and acquisition has always caused concern among researchers.From the perspective of second language semantic processing, this paper carries out an experimental study to investigate the online semantic processing of adverbial modifiers in the middle constructions by Chinese English majors from two aspects, namely the semantic constraint processing and the semantic types processing.The results show that, on the one hand, when Chinese English majors process adverbial modifiers with correct wrong or semantic constraints in the middle constructions, there are significant differences in the accuracy and reaction time.There are significant differences in the accuracy of processing adverbial modifiers with different semantic constraints among students of different English proficiency, but there is no significant difference in the reaction time.On the other hand, when they process adverbial modifier types of speed and value in the middle constructions, there are significant differences in their accuracy and reaction time, but there is no significant difference in their accuracy and reaction time when they process adverbial modifiers of different semantic types among students of different English proficiency.The study shows that second language processing and acquisition is a dynamic, complex and non-linear process.There is a dynamic competitive relationship between first and second language, which is accompanied by a mutation from attractor states to repeller states.This paper advocates that the semantic processing of adverbial modifiers in English middle constructions is a dynamic and complex process, attempting to apply Dynamic Systems Theory to the construction of a bridge between second language processing and second language acquisition.