需要修改两个文件：

第一个文件lang/zh-cn/zh-cn.js文件，搜索fontfamily

'fontfamily':{
    'songti':'宋体',
    'NSimSun':'新宋体',
    'SimSun': '仿宋',
    'FangSong_GB2312': '仿宋_GB2312',
    'YouYuan': '幼圆',
    'kaiti':'楷体',
    'heiti':'黑体',
    'lishu':'隶书',
    'yahei':'微软雅黑',
    'andaleMono':'andale mono',
    'arial': 'arial',
    'arialBlack':'arial black',
    'comicSansMs':'comic sans ms',
    'impact':'impact',
    'timesNewRoman':'times new roman'
},

第二个文件：ueditor3/ueditor.config.js文件，搜索fontfamily

,'fontfamily':[
   { label:'',name:'songti',val:'宋体,SimSun'},
      { label:'',name:'NSimSun',val:'新宋体,NSimSun'},
      { label:'',name:'SimSun',val:'仿宋,SimSun'},
      { label:'',name:'FangSong_GB2312',val:'仿宋_GB2312'},
      { label:'',name:'YouYuan',val:'幼圆'},
   { label:'',name:'kaiti',val:'楷体,楷体_GB2312, SimKai'},
   { label:'',name:'yahei',val:'微软雅黑,Microsoft YaHei'},
   { label:'',name:'heiti',val:'黑体, SimHei'},
   { label:'',name:'lishu',val:'隶书, SimLi'},
   { label:'',name:'andaleMono',val:'andale mono'},
   { label:'',name:'arial',val:'arial, helvetica,sans-serif'},
   { label:'',name:'arialBlack',val:'arial black,avant garde'},
   { label:'',name:'comicSansMs',val:'comic sans ms'},
   { label:'',name:'impact',val:'impact,chicago'},
   { label:'',name:'timesNewRoman',val:'times new roman'}
]

这两个文件修改后保存，即可实现字体加入。