With the rapid development of industry and transportation, oil has played an increasingly important role in modern civilization. In the meantime, oil spill pollution has posed a serious threat to the marine ecosystems of the world [1], [2]. Accurate and quick localization, identification, and monitoring of oil spills on the sea surface are of great significance to protect the marine ecological environment [3], [4]. Laser-induced fluorescence (LIF) is an effective way to analyze the composition of substances [5], [6]. LIF lidar has been widely used in offshore oil spill monitoring, which can not only detect oil slicks on the sea surface [7], [8], identify oil types [9], measure their thicknesses and volumes [10], [11], [12], [13], but also provide the ability to measure the concentration of dissolved oil products in the subsurface layer [14]. Nowadays, LIF spectrometers have been developed for monitoring oil, CDOM, chlorophyll etc [15], [16], [17], [18]. These LIF lidar systems can be loaded on airplanes, ships, and shore platforms for monitoring a large-scale ocean area, which owns the advantages of high measuring speed and long-distance remote sensing [19], [20], [21], [22], [23]. These devices are often high-performing but bulky, so they are suitable for the specific research of large sea areas and offshore oil disasters, but not very convenient for routinely sea monitoring and oil spill monitoring on a regional scale. In situ LIF detection instruments generally adopt semiconductor lasers as the excitation light source, which are characterized by low cost, small volume, and compact structure relatively. In situ LIF instruments can be configured with either single-wavelength lasers or multi-wavelength excitation lasers to extend analytical capabilities [24]. Such portable LIF instruments based on shipboard provide comprehensive and detailed spectral information for analyzing water quality and are easy to be applied in cruise surveys. In situ ocean observation is limited by human’s ability to make comprehensive observations in many locations due to the remoteness, harshness, and sheer geographic dimensions of the ocean environment [25]. Nowadays, drone exploitation costs are low, so compact and sensitive lidar systems have stimulated wide interest in numerous applications such as ecological monitoring and plant field diagnostics in agriculture [26], [27], [28], [29], [30]. Therefore, the UAV-based LIF lidar system is crucial to be improved due to the worsening pollution which is caused by illegal bilge water disposal, bunkering accidents, and other accidents on a small scale [31], [32], [33], [34]. With the development of laser and photoelectric detection technology, small size, high-power, low-cost laser, and high sensitivity ICCD cameras have been developed rapidly. This research presents a portable LIF lidar system that can be carried by UAV. It is composed of a transmitting and receiving module, a data processing module and a wireless transmission module, which can realize real-time monitoring of the aquatic environment. Laboratory and UAV-based experimental investigations of the LIF spectra were carried out.