煤自燃是导致矿井火灾的主要原因，一直威胁着煤矿安全生产。煤自燃是一个非常复杂的动态过程，其形成和发展是自发的、缓慢的、动态变化的放热、聚热、升温，引起燃烧的过程。判定煤自燃阶段，实现煤自燃分级预警是防治煤自燃的关键。 本文针对煤自燃阶段判定和分级预警，通过实验测试、理论分析和现场试验展开研究。针对煤自燃特征温度，采用大型煤自然发火实验、煤自燃程序升温实验和热重分析，通过煤自燃过程单一指标和复合指标、重量比和失重速率等参数，建立温度和气体的对应关系，确定了八个特征温度；基于煤自燃分子结构模型，针对煤自燃过程煤分子基团变化，进行煤氧化动力学理论、量子化学理论和相似理论分析，研究了煤分子活性基团种类、反应通道的优先顺序和煤表面活性基团的活泼性次序，找到了煤分子活性基团参与煤氧反应的规律，提出了煤自燃基团突变理论；基于煤自燃基团突变理论分析，选择了六个特征温度，划分煤自燃过程为七个阶段，确立了煤自燃阶段判定方法；针对煤自燃预警，发现了煤自燃过程中氧化气体和热解气体产生规律，研究了煤自燃标志气体和多参数指标，找到了氧气浓度区间的CO气体浓度表达方式，优选了六个煤自燃指标，分别为CO、O2、CO/ΔO2、C2H4、C2H4/C2H6和C2H2；针对容易自燃煤，实施了现场试验，实现了实验数据与现场试验数据的成功对接，量化了煤自燃指标，建立了煤自燃预警体系，确立了容易自燃煤自燃分级预警方法。 本文给出了《煤矿安全规程》中关于煤自然发火临界值、发火征兆、火灾的划分依据，为煤矿现场自然发火由被动治理向主动预防转变提供了指导。

Coal spontaneous combustion is the main cause of mine fire, which has always threatened coal mine safety. The spontaneous combustion of coal is a very complex dynamic process. Its formation and development are spontaneous, slow, and dynamically changing exothermic, calorific, and warming processes that cause combustion. To determine the coal spontaneous combustion stage and achieve the coal spontaneous combustion classification warning is the key to prevent coal spontaneous combustion. In this paper, based on the determination of coal spontaneous combustion stage and classification warning, the research is carried out through experimental test, theoretical analysis and field test. According to the characteristics of coal spontaneous combustion temperature, the corresponding relationship between temperature and gas is established by using the parameters of single and composite indexes, weight ratio and weightless rate of coal spontaneous combustion process. Eight characteristic temperatures were determined; Based on the coal spontaneous combustion molecular structure model, the coal molecular group changes in the coal spontaneous combustion process are analyzed by coal oxidation Kinetics theory, quantum chemistry theory and similar theory. The types of active groups of coal molecules, the priority order of reaction channels and the active order of active groups on coal surface were studied. Based on the analysis of coal spontaneous combustion group mutation theory, six characteristic temperatures were selected, and the coal spontaneous combustion process was divided into seven stages. According to the coal spontaneous combustion early warning, the law of oxidation gas and pyrolysis gas generation during coal spontaneous combustion was found, the coal spontaneous combustion marker gas and multiple parameter indexes were studied, and the expression method of CO gas concentration in the oxygen concentration range was found, and six coal spontaneous combustion indexs were optimized.They are CO, O2, CO/ΔO2, C2H4, C2H4/C2H6 and C2H2. For easy self-combustion coal, the field test is carried out, and the successful connection between the experimental data and the field test data is achieved, the coal spontaneous combustion index was quantified, an early warning system for coal spontaneous combustion was established, and a classification warning method for coal spontaneous combustion was improved. This paper gives the division basis for the threshold, fire signs and fire of coal spontaneous combustion in the Coal Mine Safety Regulations, and provides guidance for the transition from passive control to active prevention.