diff --git a/src/promql.ts b/src/promql.ts
index 13568fa..0b66882 100644
--- a/src/promql.ts
+++ b/src/promql.ts
@@ -1,15 +1,23 @@
 import { formatResult } from './utils'
 import axios, { AxiosRequestConfig } from 'axios'
-import { PromQLArgs, PromQLResultState } from './type/promql'
+import { PromQLArgs, PromQLParams, PromQLResultState } from './type/promql'
 import { FormatResultState, QueryResData } from './type/common'
 
 const dayjs = require('dayjs')
 class PromQL {
   url: string
   args: PromQLArgs
+  params: PromQLParams
 
   constructor(db: string) {
     this.url = '/v1/promql'
+    this.params = {
+      metrics: '',
+      selectors: [],
+      range: '',
+      field: '',
+      functions: [],
+    }
     this.args = {
       query: '',
       start: dayjs().subtract(5, 'm').unix(),
@@ -48,7 +56,81 @@ class PromQL {
     return this
   }
 
+  metrics = (metrics: string) => {
+    this.params.metrics = metrics
+    return this
+  }
+
+  selectors = (selectors: string | Object) => {
+    this.params.selectors =
+      typeof selectors === 'string'
+        ? selectors.split(',')
+        : Object.entries(selectors).map(([key, value]) => {
+            let [_, k, operation] = key.match(/^(.*?)([!~=]*)$/)
+            switch (operation) {
+              case '!':
+              case '!=':
+                operation = '!='
+                break
+              case '~':
+              case '=~':
+                operation = '=~'
+                break
+              case '!~':
+                operation = '!~'
+                break
+              case '=':
+              default:
+                operation = '='
+                break
+            }
+            return `${k}${operation}'${value}'`
+          })
+    return this
+  }
+  field = (field: string) => {
+    this.params.field = field
+    return this
+  }
+
+  range = (range: string) => {
+    this.params.range = range
+    return this
+  }
+
+  functions = (functions: string | string[]) => {
+    this.params.functions = Array.isArray(functions) ? functions : [functions]
+    return this
+  }
+
   run = async (): Promise<PromQLResultState> => {
+    if (!this.args.query) {
+      if (!this.params.metrics) {
+        return Promise.reject('wrong promQL query')
+      }
+
+      let query = this.params.metrics
+
+      if (this.params.selectors.length) {
+        if (this.params.field) {
+          this.params.selectors.push(`__field__='${this.params.field}'`)
+        }
+        query += `{${this.params.selectors.join()}}`
+      }
+
+      if (this.params.range) {
+        query += `[${this.params.range}]`
+      }
+
+      if (this.params.functions.length) {
+        this.params.functions.forEach((fn) => {
+          query = `${fn}(${query})`
+        })
+      }
+      console.log(`query:`, query)
+      this.args.query = query
+    }
+
     let res: QueryResData = await axios.post(this.url, {}, {
       params: this.args,
     } as AxiosRequestConfig)
diff --git a/src/type/promql.ts b/src/type/promql.ts
index 6fce517..2d1dfc4 100644
--- a/src/type/promql.ts
+++ b/src/type/promql.ts
@@ -13,3 +13,10 @@ export interface PromQLArgs {
   step: string
   db: string
 }
+export interface PromQLParams {
+  metrics: string
+  selectors: string[]
+  range: string
+  field: string
+  functions: string[]
+}