A gas mixing device, comprising: a housing , which is provided with an air inlet, a combustion gas inlet , and an EGR exhaust gas inlet ; a first mixing core arranged in the housing , wherein the air inlet and the combustion gas inlet respectively communicate with the first mixing core to form a mixed gas in the first mixing core ; a first measurement assembly , which is connected on the first mixing core and which is configured to provide measurement data in order to obtain a first flow rate of the mixed gas; a second mixing core arranged in the housing , wherein the EGR exhaust gas inlet and the first mixing core respectively communicate with the second mixing core ; a second measurement assembly , which is connected on the EGR exhaust gas inlet and which is configured to provide measurement data in order to obtain a second flow rate of an EGR exhaust gas; and a throat body disposed in the housing between the first mixing core and the second mixing core , the throat body comprising a depressurization section and a first smooth section connected to the depressurization section ; wherein the second mixing core comprises a guide section having a diameter larger than that of the first smooth section , and a first passage is formed between the guide section and the first smooth section , and EGR exhaust gas from the EGR exhaust gas inlet enters the first passage to mix with the mixed gas from the first smooth section of throat body ; and a second passage is formed between the first mixing core and the housing , the second passage is in communication with the combustion gas inlet , and the first mixing core is provided with a first injection port . a housing , which is provided with an air inlet, a combustion gas inlet , and an EGR exhaust gas inlet ; a first mixing core arranged in the housing , wherein the air inlet and the combustion gas inlet respectively communicate with the first mixing core to form a mixed gas in the first mixing core ; a first measurement assembly , which is connected on the first mixing core and which is configured to provide measurement data in order to obtain a first flow rate of the mixed gas; a second mixing core arranged in the housing , wherein the EGR exhaust gas inlet and the first mixing core respectively communicate with the second mixing core ; a second measurement assembly , which is connected on the EGR exhaust gas inlet and which is configured to provide measurement data in order to obtain a second flow rate of an EGR exhaust gas; and a throat body disposed in the housing between the first mixing core and the second mixing core , the throat body comprising a depressurization section and a first smooth section connected to the depressurization section ; wherein the second mixing core comprises a guide section having a diameter larger than that of the first smooth section , and a first passage is formed between the guide section and the first smooth section , and EGR exhaust gas from the EGR exhaust gas inlet enters the first passage to mix with the mixed gas from the first smooth section of throat body ; and a second passage is formed between the first mixing core and the housing , the second passage is in communication with the combustion gas inlet , and the first mixing core is provided with a first injection port . <EOS>