The invention provides an internal bus for an aerospace electronic product, which is used for performing information interaction between a master module and a plurality of slave modules. Bus signals comprise a test signal, a system signal, a digital I/O (Input/Output) signal, an auxiliary functional signal, a power supply signal and a time clock synchronization signal; a bus time sequence is classified into a main module operation period using waiting and a main module operation period not using waiting; each operation period is classified into a reading time sequence and a writing time sequence. The bus provided by the invention has high universality and compatibility specific to aerospace electronic products, and contributes to improvement of module interconnection signal quality and working reliability.