diff --git a/onnxruntime/contrib_ops/webgpu/quantization/matmul_nbits.cc b/onnxruntime/contrib_ops/webgpu/quantization/matmul_nbits.cc
index c79efee65e5c5..e6cf911e954d7 100644
--- a/onnxruntime/contrib_ops/webgpu/quantization/matmul_nbits.cc
+++ b/onnxruntime/contrib_ops/webgpu/quantization/matmul_nbits.cc
@@ -535,42 +535,23 @@ Status DP4AMatMulQuantizeProgram::GenerateShaderCode(ShaderHelper& shader) const
   shader.AddOutput("output", ShaderUsage::UseUniform);
   shader.AddOutput("scales", ShaderUsage::UseUniform);
 
-  shader.AdditionalImplementation() << R"ADDNL_FN(
-    var<workgroup> max_values : array<input_a_element_t, 4>;
- )ADDNL_FN";
-
   shader.MainFunctionBody() << R"MAIN_FN(
-  var local_a = input_a[global_idx];
-  var max_val = subgroupMax(abs(local_a));
-  var max_temp = max(max_val.xy, max_val.zw);
-  var scale = max(max_temp[0], max_temp[1]);
-  if (local_idx % sg_size == 0) {
-    max_values[local_idx / sg_size] = scale;
-  }
-  workgroupBarrier();
-
-  if (sg_size == 8)
+  var local_a : array<vec4<input_a_element_t>, 32>;
+  var max_value:vec4<input_a_element_t> = vec4<input_a_element_t>(0);
+  for (var idx:u32=0;idx<32;idx+=1)
   {
-    scale = max(max_values[0], max_values[1]);
-    scale = max(scale, max_values[2]);
-    scale = max(scale, max_values[3]);
+    local_a[idx] = input_a[workgroup_id.x*32 + idx];
+    max_value = max(max_value, abs(local_a[idx]));
   }
-  else if (sg_size == 16)
-  {
-    scale = max(max_values[0], max_values[1]);
-  }
-  else
-  {
-    scale = max_values[0];
-  }
-
-  var norm_a = local_a/scale;
-  output[global_idx] = pack4x8snorm(vec4<f32>(norm_a));
-  if (local_idx == 0)
+  var scale = max(max_value.x, max_value.y);
+  scale = max(scale, max_value.z);
+  scale = max(scale, max_value.w);
+  for (var idx:u32=0;idx<32;idx+=1)
   {
-    // 127 is the max value of signed int8 [-127,127] used by pack4x8snorm for 1.0f.
-    scales[workgroup_idx] = scale/127;
+    output[workgroup_id.x*32+idx] = pack4x8snorm(vec4<f32>(local_a[idx]/scale));
   }
+  // 127 is the max value of signed int8 [-127,127] used by pack4x8snorm for 1.0f.
+  scales[workgroup_id.x] = scale/127;
 )MAIN_FN";
   return Status::OK();
 }
@@ -838,7 +819,7 @@ Status MatMulNBits::ComputeInternal(onnxruntime::webgpu::ComputeContext& context
 
     constexpr uint32_t kBlockSizeA = 128;
     DP4AMatMulQuantizeProgram quantize_program;
-    quantize_program.SetWorkgroupSize(32);
+    quantize_program.SetWorkgroupSize(1);
     quantize_program.SetDispatchGroupSize(M * K / kBlockSizeA, 1, 1);
     TensorShape a_quant_shape{1, M, K / kU32Components};
     Tensor a_quant = context.CreateGPUTensor(DataTypeImpl::GetType<uint32_t>(), a_quant_shape);