随着移动设备的日渐普及，联机手写输入方式为化学知识的使用和分享提供了可能，而化学公式的数字化处理也逐渐成为热点。为了有效进行联机手写化学公式的识别，通过整理6种化学公式中常见的符号位置关系，提出了一种用于联机手写化学公式识别与分析的方法，该方法在处理了断笔、粘连、连笔等书写异常情况后，完成了对化学公式的切分。识别时，先利用SVM+HMM的两级分类机制识别独立的化学符号；然后以公式的语义和语法规则协助理解用户的书写原意。实验证明，该方法应用于平板电脑，对于上述3个阶段的化学公式识别均取得了理想的结果，从而为联机手写化学公式重现和重用打下了基础。

With the development of mobile devices, the pen-based input mode has provided the possibility to use and share chemical knowledge easily. As an application of ubiquitous computing, research on online handwritten chemical formulas becomes a hot area. In this paper, we conclude common relations between chemical symbols and segment a chemical formula after linking the broken strokes. Then a two-level classifier is used to recognize the isolated symbols and the formula is understood with some chemical rules. The experimental results show that our method is robust and feasible when used on Tablet PCs.