In this paper, we aim to study the transmission and evolution characteristics of femtosecond pulses in low-mode fibers. A kind of high nonlinear few-mode toluene liquid-core photonic crystal fiber (TLC-PCF) is proposed The nonlinear coefficient at the pump wavelength is about 42 W-1 . km-1. Multimode generalized nonlinear Schrodinger equation (MM-GNLSE) is used to model and solve the femtosecond pulse transmission and evolution. The energy transfer characteristics of different peak power (1 kW, 10 kW, 50 kW) are compared in this paper. When a Gaussian pulse with a central wavelength of 2000 nm, a peak power of 50 kW and a pulse width of 200 fs is transmitted in a TLC-PCF with a length of 30 cm, the supercontinuum output of 1980-2500 nm is obtained, and the energy transfer reaches the equilibrium point for the first time at 0. 02 m.The numerical results show that the energy transfer occurs in degenerate modes when a mode is excited, and it is concluded that four-wave mixing (FWM) is responsible for energy transfer between modes in TLC-PCF.In this paper, MM-GNLSE theory is innovatively adopted to analyze mode coupling, SCG and energy transfer properties in a few-mode liquid-core photonic crystal fiber with slow nonlinearity.