The present invention relates to an optical modulating device with frequency multiplying technique for electrical signals, which primary comprises a mixer, which generates a mixed data signal from a first electrical signal and a second electrical signal. The mixed data signal is then received by a first phase shift device to have its phase shifted and becomes a first shifted signal. The first electrical signal is further received by a second phase shift device to have its phase shifted and becomes a second shifted signal. The present invention further comprises an integrated electro-optic modulator (Mach-Zehnder modulator), which is used to receive an input optical signal, the mixed data signal, the first shifted signal, the second shifted signal and the first electrical signal mentioned above, the integrated electro-optic modulator will then modulates the input optical signal into a frequency multiplying output optical signal that carries the first electrical signal and the second electrical signal. The present invention can carry and transmit amplitude shift keying signals and vector modulation signals, thereby provides a more advanced optical communication transmission service.