Abstract: In view of the drawbacks of present anti-collapse plugging agents,such as kerite whose fluorescence level is high, and paraffin and polyalcohol which are easy to foam and substantially increase the viscosity of drilling fluid, which cannot satisfy the requirement of anti-collapse drilling fluid, a new kind of plugging agent JA is invited with diisocyanate, ethyl acetate and polyhydroxy compounds to composite . Fluorescence spectrophotometer and HTHP plugging spectrometer were used to study the fluorescence and plugging properties of JA and evaluated the rheological properties of JA drilling fluid. The results showed that the fluorescence intensity of JA was low, which was only 30 a.u; under the condition of 120 ℃ and 3.5 MPa, JA could rapidly plug microfissures and porous place and create a dense plugging layer. When 3% JA was added to drilling fluid, it would not thicken or viscosify the drilling fluid, posing nearly no effect on the rheological property of drilling fluid system.