In order to meet the demand of real-time spatial data processing and improve the online processing capability of photogrammetric system, a kind of online photogrammetry method is proposed. According to the proposed method, system based on embedded architecture is then designed. Online photogrammetric data processing is realized by using FPGA(Field Programmable Gate Array), ARM+DSP(Advanced RISC Machine coupled with Digit Signal Processor) and other embedded computing technologies to build specialized hardware operating environment as well as transplanting and optimizing the existing photogrammetric algorithm to the embedded system. Aerial photogrammetric experiment shows that the method can achieve high-speed and stable online processing of photogrammetric data. And the experiment also verifies the feasibility of the proposed online photogrammetric system based on embedded architecture, which can improve the processing the efficiency of photogrammetry to a higher level and broaden the application field of photogrammetry.