Some embodiments of this disclosure provide a current sample-and-hold circuit and a sensor. The current sample-and-hold circuit is used for offsetting a background photocurrent of a photodiode, and includes a capacitor and a first transconductance amplifier which has adjustable transconductance and is used for outputting a sampled current to the photodiode to offset the background photocurrent of the photodiode； one end of the capacitor is connected with a power supply VDD, the other end of the capacitor is connected with one end of the first transconductance amplifier； and the other end of the first transconductance amplifier is connected with the photodiode to output the sampled current to the photodiode to offset the background photocurrent of the photodiode. According to the embodiments of this disclosure, compared to existing technologies, the first transconductance amplifier with the adjustable transconductance is arranged in the current sample-and-hold circuit, and when the background photocurrent of the photodiode is increased, a change of a voltage of the capacitor within a large range can be avoided by increasing the transconductance of the first transconductance amplifier, so that the current sample-and-hold circuit can offset a larger background photocurrent.
