The invention relates to a tree emission gases study device, in particular to a tree volatile organic compounds collecting device which comprises an umbrella-shaped support and a transparent plastic bag. The transparent plastic bag is covered over the umbrella-shaped stand. Pipeline is communicated with a gas sampler at a place where the transparent plastic bag is fastened on a support. The probes of a hygrothermograph and a luxmeter are arranged in the transparent plastic bag. The device of the invention is easy to be arranged and dismounted, and has low cost, does no damage to the branches where gases are collected, and can realize the synchronous dynamic monitor of the temperature and humidity in the device and the solar radiation intensity and gas collecting in the gas collecting process.