Abstract: Millions of tons of oily sludge are generated annually during onshore oilfield development, which is difficult to treat and poses significant environmental risks. Existing treatment technologies are not only ineffective in treating it properly but also economically inefficient and carry risks of secondary pollution. Microbial treatment technology has attracted widespread attention due to its high degradation efficiency, environmental friendliness, and low cost. A plant-microbial fuel cell (PMFC) was constructed by using the newly isolated indigenous microorganism (Bacillus paramycoides) as the electrogenic bacteria, using oily sludge as the substrate and plants, and the effects of plant species, oil concentration, and temperature on the crude oil degradation rate and power generation performance of the PMFC were investigated. The results showed that Bacillus paramycoides could be used as an electrogenic bacterium for crude oil degradation and electricity generation. Dianthus chinensis exhibited better electricity generation and degradation capabilities than Spathiphyllum kochii and significantly higher than those of Eichhornia crassipes. The oil tolerance of Dianthus chinensis was optimal when the oil content was approximately 1%, and the suitable temperature was 25 ℃. Under the optimal environmental condition, the peak output voltage of 376.84 mV, maximum power density of 141.81 mW/m³, and crude oil degradation rate of 21.57% could be achieved. The results can provide a new approach for the treatment of oily sludge in oilfields.