A method for detecting an operating state of a photovoltaic panel, wherein the photovoltaic panel is arranged in a photovoltaic electrical system, the photovoltaic electrical system comprises a photovoltaic device and a control device, the photovoltaic device comprises the photovoltaic panel and a modulator, the control device comprises a demodulator, the photovoltaic device is connected to the control device via a direct current bus, the method comprises: detecting the operating state of the photovoltaic panel to obtain a state parameter of the photovoltaic panel; modulating, through the modulator, the state parameter of the photovoltaic panel to obtain a modulated signal, and loading the modulated signal to the direct current bus; and transmitting the modulated signal to the demodulator through the direct current bus, wherein the demodulator is configured to demodulate the modulated signal to obtain the state parameter of the photovoltaic panel; wherein a cycle of communication between the photovoltaic device and the control device is a preset cycle, and the preset cycle comprises successive periods of a first time period, a second time period and a third time period, wherein in the second time period, the modulated signal is loaded onto the direct current bus or the modulated signal is demodulated; and wherein after transmitting the modulated signal to the demodulator through the direct current bus, the method further comprises: detecting the output voltage of the direct current bus in the first time period to obtain a first voltage value; detecting the output voltage of the direct current bus in the third time period to obtain a second voltage value; determining whether a difference between the first voltage value and the second voltage value is greater than a preset threshold; determining, if the difference between the first voltage value and the second voltage value is greater than the preset threshold, that the state parameter of the photovoltaic panel is not successfully transmitted to the control device; and determining, if the difference between the first voltage value and the second voltage value is less than or equal to the preset threshold, that the state parameter of the photovoltaic panel is successfully transmitted to the control device. detecting the operating state of the photovoltaic panel to obtain a state parameter of the photovoltaic panel; modulating, through the modulator, the state parameter of the photovoltaic panel to obtain a modulated signal, and loading the modulated signal to the direct current bus; and transmitting the modulated signal to the demodulator through the direct current bus, wherein the demodulator is configured to demodulate the modulated signal to obtain the state parameter of the photovoltaic panel; wherein a cycle of communication between the photovoltaic device and the control device is a preset cycle, and the preset cycle comprises successive periods of a first time period, a second time period and a third time period, wherein in the second time period, the modulated signal is loaded onto the direct current bus or the modulated signal is demodulated; and wherein after transmitting the modulated signal to the demodulator through the direct current bus, the method further comprises: detecting the output voltage of the direct current bus in the first time period to obtain a first voltage value; detecting the output voltage of the direct current bus in the third time period to obtain a second voltage value; determining whether a difference between the first voltage value and the second voltage value is greater than a preset threshold; determining, if the difference between the first voltage value and the second voltage value is greater than the preset threshold, that the state parameter of the photovoltaic panel is not successfully transmitted to the control device; and determining, if the difference between the first voltage value and the second voltage value is less than or equal to the preset threshold, that the state parameter of the photovoltaic panel is successfully transmitted to the control device. detecting the output voltage of the direct current bus in the first time period to obtain a first voltage value; detecting the output voltage of the direct current bus in the third time period to obtain a second voltage value; determining whether a difference between the first voltage value and the second voltage value is greater than a preset threshold; determining, if the difference between the first voltage value and the second voltage value is greater than the preset threshold, that the state parameter of the photovoltaic panel is not successfully transmitted to the control device; and determining, if the difference between the first voltage value and the second voltage value is less than or equal to the preset threshold, that the state parameter of the photovoltaic panel is successfully transmitted to the control device.