Although non-linear noise exists far more widely in actual systems than linear noise, the study on non-linear noise is far from meeting the needs of practical situations as yet. The phenomenon of stochastic resonance (SR) is a non-linear cooperative effect which is jointly produced by signal, noise, and system, obviously, it is closely related to the nature of the noise. As a result, the non-linear nature of the non-linear noise has an inevitable impact on the dynamic behavior of a system, so it is of great significance to study the non-linear noise's influence on the dynamic behavior of the system. The linear harmonic oscillator is the most basic model to describe different phenomena in nature, and the quadratic noise is the most basic non-linear noise. In this paper, we consider a linear harmonic oscillator driven by an external periodic force and a quadratic damping fluctuation. For the proposed model, we focus on the effect of non-linear nature of quadratic fluctuation on the system's resonant behavior. Firstly, by the use of the Shapiro-Loginov formula and the Laplace transform technique, the analytical expressions of the first moment and the steady response amplitude of the output signal are obtained. Secondly, by studying the impacts of noise parameters and system intrinsic frequency, the non-monotonic behaviors of the steady response amplitude are found. Finally, numerical simulations are presented to verify the effectiveness of the analytical result. According to the research, we have the following conclusions: (1) The steady response amplitude is a non-monotonic function of coefficients of the quadratic damping fluctuation. Furthermore, the non-linear damping fluctuation is easier to contribute the system's enhancing response to the external periodic signal than the linear fluctuation. (2) The evolution of the steady response amplitude versus noise intensity presents more resonant behaviors. One-peak SR phenomenon and double-peak SR phenomenon are observed at different values of coefficients of the quadratic noise, particularly, the SR phenomenon disappears at the positive quadratic coefficient of the quadratic noise. (3) The evolution of the steady response amplitude versus the system intrinsic frequency presents true resonance, i. e. the phenomenon of resonance appears when the external signal frequency is equal to the system intrinsic frequency. True resonance is not observed in the linear harmonic oscillator driven by a linear damping fluctuation as yet. In conclusion, all the researches show that the non-linear nature of non-linear noise plays a key role in system's resonant behavior, in addition, the non-linear damping fluctuation is conductive to the detection and frequency estimation of weak periodic signal.