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option = {
  xAxis: {
    type: 'category',
    data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
  },
  yAxis: {
    type: 'value'
  },
  series: [
    {
      data: [150, 230, 224, 218, 135, 147, 260],
      type: 'line',
      
    }
  ]
};

效果： 

需要添加参数markLine

option = {
  xAxis: {
    type: 'category',
    data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
  },
  yAxis: {
    type: 'value'
  },
  series: [
    {
      data: [150, 230, 224, 218, 135, 147, 260],
      type: 'line',
      markLine: {
        symbol: 'none',
        silent: true,
        lineStyle: { normal: { type: 'dashed' } },
        label: { position: 'start' },
        data: [
          {
            yAxis: 250,
            lineStyle: { width: 1.656, color: '#ff6367' },
            label: { show: false }
          },
          {
            yAxis: 150,
            lineStyle: { width: 1.656, color: '#46C67F' },
            label: { show: false }
          }
        ]
      },
      
    }
  ]
};

效果: