###### Abstract
Deproteinization and deacetylation react at the same time, eliminating the intermediate washing process. The alkali liquor in the reaction can be reused after the crystallization purification treatment after being utilized to a certain extent. The production process is simple, the production time is shortened, energy consumption and environmental pollution are reduced, and the purposes of economic, efficient and green environmental protection are truly achieved. Chitosan biochemistry performance is closely related to its biomedical applications. Molecular structural, physiochemical, and bio-functional aspects were taken into account to study chitosan biochemistry performance according to the published literature [14; 15]. Infrared spectroscopy and thermogravimetric analysis are commonly applied to study and analyze the quality of the stability of chitosan. The group composition and variation in its molecular structure can be observed through the former, while the thermal stability (TS) characteristics can be analyzed beside the latter [16; 17]. [PERSON] et al. [18] characterized the biochemical efficacy of fungi chitosan by circular dichroism, and the results showed that the isolated chitosan could be used for specific drug delivery applications. [PERSON] et al. [19] determined chitosan M\({}_{\rm W}\) and DD and studied the structural stability and biocompatibility. [PERSON] et al. [20] reported that the \(\beta\)-chitosan extracted from the squid gladius after a high pressure (500 MPa) treatment could significantly improve the fat binding capacity (FBC) and water binding capacity (WBC), and had higher antioxidant capacity. Recently, the industry community is mainly interested in \(\alpha\)-chitosan extracted from shrimp and crab shells, but the content of minerals is high, while the chitosan is relatively low in shrimp and crab shells. The transparent sword-shaped skeleton of the squid is called the gladius or pen, and usually is a by-product in squid industrial processing. To improve the utilization rate of marine resources and reduce environmental pollution, the squid gladius, which is significant in yield and holds valuable bioactive substancessuch as \(\beta\)-chitin, protein and fat, can be used as a good source of chitosan products with potential application prospects in the food and pharmaceutical trades [21]. Currently, some researchers have studied the extraction and structure characterization of chitosan from marine biological by-products, and some interesting new applications have emerged. With the continuous improvement of the understanding of chitosan and the further deepening of the research on its application, chitosan has attracted more and more attention. The quality standard of chitosan established recently is only limited to the physiochemical properties, but the related biological performance is not involved yet. The comprehensive evaluation method for chitosan biochemistry performance, which is helpful to control the biological application of chitosan from different marine sources, has not been reported. A weighted composite index method groups the same or different index values for statistical processing to standardize the index values of different measurement units and different properties, to give various weights according to the importance, and finally to transform them into a weighted composite index. In this paper, the estimation method of the chitosan biochemistry performance index was established based on the close relationship between chitosan properties and the biomaterials application, which can provide scientific guidance for chitosan biological application.