Abstract This paper proposes a nondestructive method for on-line estimation of eggshell strength based on acoustic resonance analysis. The system employed digital signal processing (DSP, TMS320F2812) as core processor to collect and analyze the response signal of eggshell. Fast Fourier Transform (FFT) and Discrete Cosine Transform (DCT) were used to transform the time domain signal into frequency domain signal for next analysis. Synergy interval partial least square (si-PLS) combined with multiple stepwise regression was used to establish a linear calibration model for eggshell strength measurement. The performance of the optimal model using 11 frequency variables was achieved, with R (correlation coefficient) of 0.776 and RMSEP (root mean square error of prediction) of 3.010 in prediction set. Good consistence confirmed that the acoustic resonance system has significant potential in on-line estimation of the eggshell strength. Industrial relevance With processing and handling procedure continues increasing in egg production, the possibility of the presence of eggshell crack sharply increases. In such case, it is essential to measure the strength of eggshell, so as to maintain the balance between eggshell strength and the handling load in the processing of egg collection, sorting and transportation. This work proposes a nondestructive method for on-line estimation of eggshell strength based on acoustic resonance analysis, and builds a robust calibration model to improve the prediction ability. The research data presents a potential way for on-line and non-destructive measurement of eggshell strength in egg industry.